The Battle of the Twin Tunnels: Korea, 1 February 1951

1988 ◽  
Author(s):  
Ted C. Chilcote
Keyword(s):  
Twin Tunnels

Determining The Minimum Distance Between Centers of Two Parallel Tunnels to Apply The Law of Super Position in Order to Calculate Subsidence by Using The Software FLAC 3D

2015 ◽  
Vol 1 (1) ◽  
pp. 13-20
Author(s):  
Hamid Reza Samadi ◽  
Mohammad Reza Samadi
Keyword(s):  
Minimum Distance ◽  
Surface Subsidence ◽  
Urban Traffic ◽  
Underground Structures ◽  
Rapid Population Growth ◽  
The North ◽  
Flac 3D ◽  
The Law ◽  
3D Software ◽  
Twin Tunnels

Due to the development of cities as well as rapid population growth, urban traffic is increasing nowadays. Hence, to improve traffic flow, underground structures such as metro, especially in metropolises, are inevitable. This paper is a research on the twin tunnels Of Isfahan's metro between Shariaty station and Azadi station from the North towards the South. In this study, simultaneous drilling of subway's twin tunnels is simulated by means of Finite Difference Method (FDM) and FLAC 3D software. Moreover, the lowest distance between two tunnels is determined in a way that the Law of Super Position could be utilized to manually calculate the amount of surface subsidence, resulted by drilling two tunnels, by employing the results of the analysis of single tunnels without using simultaneous examination and simulation. In this paper, this distance is called "effective distance". For this purpose, first, the optimum dimensions of the model is chosen and then, five models with optimum dimensions will be analyzed separately, each of which in three steps. The results of analyses shows that the proportions (L/D) greater than or equal 2.80, the Law of Super Position can be applied for prediction of surface subsidence, caused by twin tunnels' construction

Stability Analysis of the Nanjung Water Diversion Twin Tunnels based on Convergence Measurement

2019 ◽  
Vol 1 (1) ◽  
pp. 49-60
Author(s):  
Simon Heru Prassetyo ◽  
Ganda Marihot Simangunsong ◽  
Ridho Kresna Wattimena ◽  
Made Astawa Rai ◽  
Irwandy Arif ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Convergence Rate ◽  
Critical Strain ◽  
Convergence Rates ◽  
Strain Analysis ◽  
Water Diversion ◽  
Tunnel Face ◽  
Tunnel Stability ◽  
The Stability ◽  
Twin Tunnels

This paper focuses on the stability analysis of the Nanjung Water Diversion Twin Tunnels using convergence measurement. The Nanjung Tunnel is horseshoe-shaped in cross-section, 10.2 m x 9.2 m in dimension, and 230 m in length. The location of the tunnel is in Curug Jompong, Margaasih Subdistrict, Bandung. Convergence monitoring was done for 144 days between February 18 and July 11, 2019. The results of the convergence measurement were recorded and plotted into the curves of convergence vs. day and convergence vs. distance from tunnel face. From these plots, the continuity of the convergence and the convergence rate in the tunnel roof and wall were then analyzed. The convergence rates from each tunnel were also compared to empirical values to determine the level of tunnel stability. In general, the trend of convergence rate shows that the Nanjung Tunnel is stable without any indication of instability. Although there was a spike in the convergence rate at several STA in the measured span, that spike was not replicated by the convergence rate in the other measured spans and it was not continuous. The stability of the Nanjung Tunnel is also confirmed from the critical strain analysis, in which most of the STA measured have strain magnitudes located below the critical strain line and are less than 1%.

scholarly journals 3D FEM Model on the Parameters’ Influence of EPB-TBM on Settlements of Single and Twin Metro Tunnels During Construction

2021 ◽  
Author(s):  
Masoud Forsat ◽  
Mohammad Taghipoor ◽  
Masoud Palassi
Keyword(s):  
Three Dimensional ◽  
Injection Pressure ◽  
Effective Parameters ◽  
Grout Injection ◽  
3D Fem ◽  
Supporting Pressure ◽  
Epb Tbm ◽  
The Face ◽  
Clear Distance ◽  
Twin Tunnels

AbstractThe present research exposes the investigation on three-dimensional modeling of the single and twin metro tunnels for the case of the Tehran metro line. At first, simulation implemented on the comparison of the ground movements in the single and twin tunnels. Then the simulation has been performed on the influence of effective parameters of EPB-TBM on the surface settlements throughout excavation. The overcutting, shield conicity, grouting, and the final lining system modeled and the influence of face supporting pressure, grout injection pressure, as well as the clear distance of the tunnels, has been analyzed. The initial results showed a valid ground settlement behavior. The maximum settlements occurred at the end of the shield tail and it was higher in the single tunnel. The face supporting pressure had more effect on the surface settlement in comparison to the grout injection pressure. By increasing the face pressure in the single tunnel, the place of maximum settlement moved back while the grout pressure is insignificant for decreasing the settlements. Furthermore, the influence of the clear distance in the twin tunnels led to zero after the length of 30 m. Accordingly, for more distances, the tunnels must be examined independently and as two different single tunnels.

Comparison of different damping materials during train vibration at twin tunnels by similarity experiment and DEM

2022 ◽  
Vol 317 ◽  
pp. 126054
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Fuming Kuang ◽  
Wei Wang ◽  
Hong Guo
Keyword(s):  
Damping Materials ◽  
Train Vibration ◽  
Twin Tunnels

Twin tunnels excavated in mixed face conditions

2019 ◽  
pp. 6209-6218
Author(s):  
M.A.A.P. Silva ◽  
F.L. Gonçalves ◽  
A.A. Ferreira ◽  
H.C. Rocha
Keyword(s):  
Twin Tunnels

scholarly journals Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration

2021 ◽  
Vol 11 (16) ◽  
pp. 7577
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Wei Wang ◽  
Xiancong Meng ◽  
Hong Guo
Keyword(s):  
Dynamic Characteristics ◽  
Large Diameter ◽  
Horizontal Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Decisive Factor ◽  
Cross River ◽  
Static Responses ◽  
Train Vibration ◽  
Twin Tunnels

Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.

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